Investigators of the mass sex slaying case involving John Wayne Gacy say they have found evidence to link Gacy to the one murder with which he has been charged.

A down-filled jacket belonging to Robert Piest, 15, one of 32 teen-aged youths and young men Gacy, 36, said he murdered was found beneath flooring of the laundry room in Gacy's house police said Friday. Investigators said the jacket was exactly where Gacy said he had hid it. Relatives of the Piest identified the jacket. Police said they have not found his body.

Gacy said he dumped the bodies of Piest and four other victims in area rivers. Two bodies have been found in the water.

Searchers have found 26 bodies in the crawl space beneath Gacy's house and one beneath the garage in an unincorporated area northwest of the city. They dug again Friday, without finding more bodies.

In another development in the Gacy case, a Circuit Court has ruled that a radio station may broadcast an interview in which the Cook County medical examiner offers his personal views about Gacy's sanity.

Last week, during taping of a show on station WMAC, medical examiner Dr. Robert Stein said the "well thought-out manner" in which more than two dozen bodies were buried in the crawl space was evidence of Gacy's sanity.